Early diagnosis of bacterial infection in patients with septicopyemia by laboratory analysis of PCT, CRP and IL-6

The aim of the present study was to investigate the early diagnostic values of measuring procalcitonin (PCT), C-reactive protein (CRP), and interleukin-6 (lL-6) levels in patients with bacterial infections and septicopyemia. Ninety-two patients with septicopyemia who were diagnosed and treated in the First Affiliated Hospital of Fujian Medical University between December 2012 and October 2013 were randomly selected. Based on results of hemoculture, the patients were divided into the Gram-negative bacterial infection group (n=47) and the Gram-positive bacterial infection group (n=45). Immune nephelometry was used for measuring serum CRP levels, electrochemiluminescence assay was used to measure serum PCT and IL-6. The levels of serum CRP, PCT, and IL-6 in the Gram-negative bacterial infection group were significantly higher than in the Gram-positive group. Analysis with Spearman's correlation coefficient showed that there were positive correlations between the levels of PCT and CRP, and between PCT and IL-6 (P<0.05). The diagnosis of Gram-negative bacterial infections was as follows: The area under the PCT curve was 0.974 (P<0.05) with sensitivity and specificity of 96.8 and 93.5%, respectively. The area under the CRP curve was 0.953 (P<0.05) with sensitivity and specificity of 94.2 and 91.7%, respectively. The area under the IL-6 curve was 0.925 (P<0.05) with sensitivity and specificity of 93.6 and 90.5%, respectively. The diagnosis of Gram-negative bacterial infections was as follows: The area under the PCT curve was 0.854 (P<0.05) with sensitivity and specificity of 92.7 and 91.8%, respectively. The area under the CRP curve was 0.832 (P<0.05) with sensitivity and specificity of 90.2 and 89.3%, respectively. The area under the IL-6 curve was 0.817 (P<0.05) with sensitivity and specificity of 89.4 and 81.5%, respectively. In conclusion, PCT, CRP, and lL-6 can act as early diagnostic markers for bacterial infections in patients with septicopyemia.